This invention relates to a spinning device for open end spinning machines, and more particularly to a device for the separation of dirt from fibers in the spinning device.
As is well known in the art, there is a spinning device for an open end spinning machine of the type comprising a rotary spinning chamber, feeding and combing means for feeding a supplied sliver into the rotary spinning chamber, and a discharge channel through which the finished yarn is withdrawn. The feeding and combing means includes a combing roller to which the sliver is fed and combed out into individual fibers. By the combing roller, the individual fibers are fed to a removal position thereof and hence into the rotating spinning chamber. Along the path of the individual fibers to the removal position, there is a dirt discharging opening through which dirt contained in the sliver, such as husks, neps or short fibers having a length shorter than the width of the dirt discharge opening, is thrown out by centrifugal force toward a dirt collecting chamber. The dirt collecting chamber is provided with an air inlet and outlet to produce an air current flowing therethrough, thereby removing the dirt particles out of the dirt collecting chamber. In order to prevent the fibers from passing out through the dirt discharge opening, that is to carry out an efficient separation of the dirt from the fibers, there is provided in the housing for the feeding and combing means a dirt separating channel through which an air current is introduced into the fibers at a position near the dirt discharge opening. However, in fact, an amount of fibers passing out through the dirt discharge opening depends on various conditions, such as the circumferential speed of the combing roller, the magnitude of negative pressure provided by the negative pressure source, the type of material to be spun, and so on. It is therefore understood that if the dirt separating channel is always of the same configuration, regardless of the above-mentioned conditions, the rate of the fibers to the dirt particles in the dirt collecting chamber will be changed with the abovementioned conditions. Particularly, in the case where removal of fibers becomes excessive, the production rate of finished yarn is undesirably decreased.